项目环境:
开发环境:IntelliJ IDEA 2019.3.1 ,JDK1.8 ,MySQL: 5.6.47
采用远程数据库连接:使用ailiyun ESC CentOS 7.0项目技术:
学会使用mybatis-generator自动部署代码
学会使用tk.mybatis插件进行数据库的操作
学会实现父子表管子查询
项目资源连接:示例源代码
项目说明
本项目采用mybatis-generator的自动生成插件和Tk插件结合,实现对父子表的联合查询,使返回结果包括父表信息和它的子表每个子数据信息。
项目准备
创建数据库schooldb
使用Navicat创建数据库schooldb
,并运行下面的sql文件
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for tbl_student
-- ----------------------------
DROP TABLE IF EXISTS `tbl_student`;
CREATE TABLE `tbl_student` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`teacher_id` bigint(20) NULL DEFAULT NULL,
`name` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL COMMENT '学生姓名',
`age` int(11) NULL DEFAULT NULL COMMENT '年龄',
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 8 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact;
-- ----------------------------
-- Records of tbl_student
-- ----------------------------
INSERT INTO `tbl_student` VALUES (1, 1, '小明', 15);
INSERT INTO `tbl_student` VALUES (2, 1, '小李', 15);
INSERT INTO `tbl_student` VALUES (3, 1, '小红', 14);
INSERT INTO `tbl_student` VALUES (4, 2, '小李', 14);
INSERT INTO `tbl_student` VALUES (5, 2, '王二', 15);
INSERT INTO `tbl_student` VALUES (6, 2, '张三', 13);
-- ----------------------------
-- Table structure for tbl_teacher
-- ----------------------------
DROP TABLE IF EXISTS `tbl_teacher`;
CREATE TABLE `tbl_teacher` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL COMMENT '老师姓名',
`age` int(11) NULL DEFAULT NULL COMMENT '老师年龄',
`phone` int(11) NULL DEFAULT NULL COMMENT '手机号',
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact;
-- ----------------------------
-- Records of tbl_teacher
-- ----------------------------
INSERT INTO `tbl_teacher` VALUES (1, '王老师', 45, 1596369856);
INSERT INTO `tbl_teacher` VALUES (2, '李老师', 32, 1358948956);
SET FOREIGN_KEY_CHECKS = 1;
项目结构
一、依赖与配置
依赖
pom.xml
<dependencies>
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper-spring-boot-starter</artifactId>
<version>2.0.4</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.1</version>
</dependency>
<!-- 增加配置数据库连接池的依赖-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<!-- 加入对应mysql版本的mysql-connector-java版本-->
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-maven-plugin</artifactId>
<version>1.3.7</version>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<!-- 加入对应mysql版本的mysql-connector-java版本-->
<version>5.1.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/tk.mybatis/mapper -->
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
<version>4.1.5</version>
</dependency>
</dependencies>
<configuration>
<!--mybatis generator插件配置文件位置,默认值${basedir}/src/main/resources/generatorConfig.xml-->
<configurationFile>${basedir}/src/main/resources/mybatis-generator.xml</configurationFile>
<overwrite>true</overwrite>
<verbose>true</verbose>
</configuration>
</plugin>
</plugins>
</build>
配置application.properties
#远程数据库连接
spring.datasource.url=jdbc:mysql://121.40.83.80:3306/schooldb?characterEncoding=UTF-8&useSSL=false
#数据库用户名
spring.datasource.username=alvin
#数据库密码
spring.datasource.password=123456
#数据源类型
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
mybatis.mapper-locations=classpath:/mapper/*.xml
配置Tk<Mapper>
在utils包下 创建TkMapper.java类
/**
* 继承
* @param <T>
*/
public interface TkMapper<T> extends Mapper<T>, MySqlMapper<T> {
//特别注意,该接口不能被扫描到,否则会出错
}
配置mybatis-generator.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<properties resource="application.properties"/>
<context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
<property name="beginningDelimiter" value="`"/>
<property name="endingDelimiter" value="`"/>
<plugin type="tk.mybatis.mapper.generator.MapperPlugin">
<property name="mappers" value="com.alvin.mybatis.utils.TkMapper"/>
<property name="caseSensitive" value="true"/>
<property name="forceAnnotation" value="true"/>
<property name="beginningDelimiter" value="`"/>
<property name="endingDelimiter" value="`"/>
</plugin>
<commentGenerator>
<!-- 这个元素用来去除指定生成的注释中是否包含生成的日期 false:表示保护 -->
<!-- 如果生成日期,会造成即使修改一个字段,整个实体类所有属性都会发生变化,不利于版本控制,所以设置为true -->
<property name="suppressDate" value="true" />
<!-- 是否去除自动生成的注释 true:是 : false:否 -->
<property name="suppressAllComments" value="false" />
</commentGenerator>
<!--数据库链接URL,用户名、密码 -->
<jdbcConnection driverClass="com.mysql.jdbc.Driver"
connectionURL="jdbc:mysql://121.40.83.80:3306/schooldb"
userId="alvin"
password="123456">
</jdbcConnection>
<javaTypeResolver type="org.mybatis.generator.internal.types.JavaTypeResolverDefaultImpl">
<!--
true:使用BigDecimal对应DECIMAL和 NUMERIC数据类型
false:默认,
scale>0;length>18:使用BigDecimal;
scale=0;length[10,18]:使用Long;
scale=0;length[5,9]:使用Integer;
scale=0;length<5:使用Short;
-->
<property name="forceBigDecimals" value="false"/>
</javaTypeResolver>
<!-- java模型创建器,是必须要的元素
负责:1,key类(见context的defaultModelType);2,java类;3,查询类
targetPackage:生成的类要放的包,真实的包受enableSubPackages属性控制;
targetProject:目标项目,指定一个存在的目录下,生成的内容会放到指定目录中,如果目录不存在,MBG不会自动建目录
-->
<javaModelGenerator targetPackage="com.alvin.mybatis.model" targetProject="src/main/java">
<!-- 是否允许子包,即targetPackage.schemaName.tableName -->
<property name="enableSubPackages" value="true"/>
<!-- 是否对model添加 构造函数 -->
<property name="constructorBased" value="true"/>
<!-- 是否对类CHAR类型的列的数据进行trim操作 -->
<property name="trimStrings" value="true"/>
<!-- 建立的Model对象是否 不可改变 即生成的Model对象不会有 setter方法,只有构造方法 -->
<property name="immutable" value="false"/>
</javaModelGenerator>
<!-- 生成SQL map的XML文件生成器,
注意,在Mybatis3之后,我们可以使用mapper.xml文件+Mapper接口(或者不用mapper接口),
或者只使用Mapper接口+Annotation,
所以,如果 javaClientGenerator配置中配置了需要生成XML的话,这个元素就必须配置
targetPackage/targetProject:同javaModelGenerator
-->
<sqlMapGenerator targetPackage="mybatis" targetProject="src/main/resources">
<!-- 在targetPackage的基础上,根据数据库的schema再生成一层package,最终生成的类放在这个package下,默认为false -->
<property name="enableSubPackages" value="true"/>
</sqlMapGenerator>
<!-- 对于mybatis来说,即生成Mapper接口,注意,如果没有配置该元素,那么默认不会生成Mapper接口
targetPackage/targetProject:同javaModelGenerator
type:选择怎么生成mapper接口(在MyBatis3/MyBatis3Simple下):
1,ANNOTATEDMAPPER:会生成使用Mapper接口+Annotation的方式创建(SQL生成在annotation中),不会生成对应的XML;
2,MIXEDMAPPER:使用混合配置,会生成Mapper接口,并适当添加合适的Annotation,但是XML会生成在XML中;
3,XMLMAPPER:会生成Mapper接口,接口完全依赖XML;
注意,如果context是MyBatis3Simple:只支持ANNOTATEDMAPPER和XMLMAPPER
-->
<javaClientGenerator targetPackage="com.alvin.mybatis.mapper" type="XMLMAPPER" targetProject="src/main/java">
<!-- 在targetPackage的基础上,根据数据库的schema再生成一层package,最终生成的类放在这个package下,默认为false -->
<property name="enableSubPackages" value="true"/>
</javaClientGenerator>
<!-- 要生成哪些表 -->
<table tableName="tbl_student" domainObjectName="Student" enableCountByExample="false" enableUpdateByExample="false"
enableDeleteByExample="false" enableSelectByExample="false"
selectByExampleQueryId="false">
<generatedKey column="id" sqlStatement="JDBC" identity="true"/>
</table>
<table tableName="tbl_teacher" domainObjectName="Teacher" enableCountByExample="false" enableUpdateByExample="false"
enableDeleteByExample="false" enableSelectByExample="false"
selectByExampleQueryId="false">
<generatedKey column="id" sqlStatement="JDBC" identity="true"/>
</table>
<table tableName="tbl_teacher_student" domainObjectName="TeacherStudent" enableCountByExample="false" enableUpdateByExample="false"
enableDeleteByExample="false" enableSelectByExample="false"
selectByExampleQueryId="false">
<generatedKey column="id" sqlStatement="JDBC" identity="true"/>
</table>
</context>
</generatorConfiguration>
配置启动类
这里需要在启动类加入一个注解@MapperScan(basePackages = "com.alvin.mybatis.mapper")
,注意它的引包是import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication
//com.alvin.mybatis.mapper是我们扫描.mapper的地址
@MapperScan(basePackages = "com.alvin.mybatis.mapper")
public class MybatisApplication {
public static void main(String[] args) {
SpringApplication.run(MybatisApplication.class, args);
}
}
配置data sources
二、自动生成
自动生成结果如下
三、实现父子表查询
数据层
- StudentDto.java
public class StudentDto {
private Long id;
private String name;
private Integer age;
private Long teacherId;
//省略setter/getter方法
}
- TeacherDto.java
public class TeacherDto {
private Long id;
private String name;
private Integer age;
private Integer phone;
private List<StudentDto> dtoList;
//省略setter/getter方法
}
控制层
- TestController.java
@Controller
public class TestController {
@Autowired
TestService testService;
@ResponseBody
@GetMapping("/test")
public List<TeacherDto> search(
@RequestParam Long id
){
return testService.search(id);
}
}
业务逻辑层
- TestService.java
@Service
public class TestService {
@Autowired
StudentMapper studentMapper;
@Autowired
TeacherMapper teacherMapper;
public List<TeacherDto> search(Long id){
List<TeacherDto> repList = new ArrayList<>();
TeacherDto teacherDto = new TeacherDto();
//查询该老师的所有信息
Teacher teacher = teacherMapper.selectByPrimaryKey(id);
BeanUtils.copyProperties(teacher,teacherDto);
repList.add(teacherDto);
//查询该老师的所有学生
Example example = new Example(Student.class);
example.createCriteria().andEqualTo("teacherId",id);
List<Student> students = studentMapper.selectByExample(example);
//查询每个学生的个人信息
List<StudentDto> studentDtoList = new ArrayList<>();
for(Student student : students){
StudentDto studentDto = new StudentDto();
BeanUtils.copyProperties(student,studentDto);
studentDtoList.add(studentDto);
teacherDto.setDtoList(studentDtoList);
}
return repList;
}
}
也可以根据java8的特性使用stream代替for迭代
@Service
public class TestService {
@Autowired
StudentMapper studentMapper;
@Autowired
TeacherMapper teacherMapper;
public List<TeacherDto> search(Long id){
List<TeacherDto> repList = new ArrayList<>();
TeacherDto teacherDto = new TeacherDto();
//查询该老师的所有信息
Teacher teacher = teacherMapper.selectByPrimaryKey(id);
BeanUtils.copyProperties(teacher,teacherDto);
repList.add(teacherDto);
//查询该老师的所有学生
Example example = new Example(Student.class);
example.createCriteria().andEqualTo("teacherId",id);
List<Student> students = studentMapper.selectByExample(example);
//查询每个学生的个人信息
List<StudentDto> list = students.stream().map(student -> {
StudentDto studentDto = new StudentDto();
BeanUtils.copyProperties(student, studentDto);
return studentDto;
}).collect(Collectors.toList());
teacherDto.setDtoList(list);
return repList;
}